Katherine Barlow was Green Lake's school teacher. She made the best spiced peaches in Texas. The children loved Miss Katherine so did the men she taught. One of them, Trout Walker, was in love with Kate. Kate, however, loved the black onion picker, Sam. One day, when Sam went to go deliver some onions to Kate, he noticed the leaking roof. He told her he'd fix it for her in exchange for 3 jars of peaches. Every time he fixed one thing, he'd find another thing to fix for her. This made them develop a relationship together. One day her and Sam were discovered kissing each other. This was not allowed in the town at the time. This ended with Sam being shot and killed along with Mary Lou, his beloved and old donkey. Louis Sachar stated in an interview that Kate Barlow is his favorite character from Holes.
Kate became a famous outlaw after Sam was killed. She robbed numerous banks in Texas. She only kisses the men that she killed. She robbed Stanley's ancestor, Stanley Yelnats I which is proved that Trout's granddaughter, The Warden is looking for the Yelnats family treasure.
Many years later, Kate returns to the lake sitting against Sam's boat "Mary Lou." Trout and his wife, Linda (one of Kate's former students) aim their guns at her and ask her where the treasure is. Kate replied "Go ahead and kill me, Trout, but I sure hope you like to dig. Cause you're going to be digging for a long time. It's a big vast wasteland out there. You, and your children, and their children, can dig for the next hundred years and you'll never find it." Then, she grabs a yellow-spotted lizard which bites her wrist. Kate then dies laughing, telling them, "You'd better start diggin' Trout." In the book, she merely says "Start digging" before she dies, as the end of the chapter too says, 'Kate Barlow died laughing).